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Date: Tue, 09 Apr 2024 15:22:00 +0200
Message-Id: <D0FMGOEWQC1O.30D61WTXL4087@kernel.org>
Cc: "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
From: "Michael Walle" <mwalle@kernel.org>
To: "FLAVIO SULIGOI" <f.suligoi@asem.it>, "Tudor Ambarus"
 <tudor.ambarus@linaro.org>, "Pratyush Yadav" <pratyush@kernel.org>, "Miquel
 Raynal" <miquel.raynal@bootlin.com>, "Richard Weinberger" <richard@nod.at>,
 "Vignesh Raghavendra" <vigneshr@ti.com>
Subject: Re: EXTERNAL: Re: [PATCH 1/1] mtd: spi-nor: everspin: add em004lxb
 entry
References: <20240405100104.480779-1-f.suligoi@asem.it>
 <20240405100104.480779-2-f.suligoi@asem.it>
 <D0C9NCOMI27O.2VW2U3FNFTSPK@kernel.org>
 <PH0PR22MB3789719A62A1EE483C9FDF76F9072@PH0PR22MB3789.namprd22.prod.outlook.com>
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 <PH0PR22MB3789719A62A1EE483C9FDF76F9072@PH0PR22MB3789.namprd22.prod.outlook.com>
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Hi,

On Tue Apr 9, 2024 at 2:07 PM CEST, FLAVIO SULIGOI wrote:
> > On Fri Apr 5, 2024 at 12:01 PM CEST, Flavio Suligoi wrote:
> > > Add the Everspin EM0004LXB 4Mb (512KB) Industrial STT-MRAM Persistent
> > > Memory.
> > > This device is JEDEC compatible (JESD251 and JESD251-1), but it is no=
t
> > > able to provide SFDP information.
> >=20
> > Did you try the at25 driver if it will fit your usecase? Judging from
> > your last response, it sounds like it will do.
>
> Yes, you are right, it works with at25 driver!
> Thanks!

Good news :)

> At the moment I have to use a page size of 256 bytes, using "atmel,at25".
> Since the Everspin EM0004LXB MRAM doesn't have problem with any page size
> (theoretically I could use a single page size of 512KB), can I update the
> at25.c driver with a support for the EM0004LXB MRAM, as already done for
> the Cypress fm25 F-RAM?

Feel free to propose a patch. Keep in mind that it is another ML and
maintainer. Just use get_maintainer.pl. Keep me on CC if you like.

-michael

> >=20
> > >
> > > Link: https://www.everspin.com/file/158244/download
> > >
> > > Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
> > > ---
> > >  drivers/mtd/spi-nor/everspin.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/mtd/spi-nor/everspin.c
> > > b/drivers/mtd/spi-nor/everspin.c index 5f321e24ae7d..4741930ce9a8
> > > 100644
> > > --- a/drivers/mtd/spi-nor/everspin.c
> > > +++ b/drivers/mtd/spi-nor/everspin.c
> > > @@ -31,6 +31,14 @@ static const struct flash_info everspin_nor_parts[=
]
> > =3D {
> > >  		.size =3D SZ_512K,
> > >  		.sector_size =3D SZ_512K,
> > >  		.flags =3D SPI_NOR_NO_ERASE | SPI_NOR_NO_FR,
> > > +	}, {
> > > +		.id =3D SNOR_ID(0x6b, 0xbb, 0x13),
> > > +		.name =3D "em004lxb",
> > > +		.size =3D SZ_512K,
> > > +		.sector_size =3D SZ_512K,
> > > +		.flags =3D SPI_NOR_NO_ERASE | SPI_NOR_NO_FR | SPI_NOR_HAS_LOCK
> > |
> >=20
> > Will it also work without SPI_NOR_NO_ERASE? Also, the flash supports
> > fast read, so drop NO_FR. Also, please have a look at [1] for the
> > testing requirements.
> >=20
> > Thanks.
> > -michael
> >=20
> > > +			 SPI_NOR_HAS_TB | SPI_NOR_4BIT_BP | SPI_NOR_BP3_SR_BIT6,
> > > +		.no_sfdp_flags =3D SPI_NOR_SKIP_SFDP,
> > >  	}
> > >  };
> > >
> >=20
> > [1] https://docs.kernel.org/driver-api/mtd/spi-nor.html
>
> Thanks and best regards,
> Flavio


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